The present invention relates to an electric control circuit for a safety apparatus adapted to be actuated by an electrically operated actuator, and moe particularly to an electric control circuit of the type in which a storage condenser is connected with a primary electric power source in the form of a vehicle battery to ensure supply of electric energy to the actuator even when electric energy from the primary power source is unavailable due to disconnection of a primary power supply circuit for the actuator in the occurrence of a vehicle collision.
In such an electric control circuit as noted above, the actuator is connected in series with the primary power source through a normally open switch, and the storage condenser is connected in parallel with the switch and actuator to be discharged through the actuator upon closure of the switch. In general, the vehicle battery is assembled within an engine room compartment, and the switch is mounted on the front bumper of the vehicle or a central portion of the vehicle chassis. Meanwhile, the actuator is housed within the safety apparatus located in the passenger compartment, and the storage condenser is housed within a sealed case located adjacent to the instrument panel of the vehicle. In the electric wiring of the control circuit, a number of conductors leading from the vehicle battery are connected at a long distance with the condenser, switch and actuator. If the conductors are shorted with the ground or another conductor in the occurrence of a vehicle collision, the condenser may not be discharged through the actuator, and the safety apparatus then remains inoperative. This reduces the reliability of the safety apparatus.